CMOS (Complementary Metal Oxide Semiconductor) image sensors (CIS) have features capable of setting readout addresses relatively freely with respect to a CCD (Charge Coupled Device) image sensor.
For example, image sensors are widely used which include functions such as “addition” for simultaneously reading out a signal of a plurality of pixels, “decimation” for intermittently reading out the signal while skipping rows or columns, and “excision” for reading out the signal only from a portion of the pixels, in addition to readout of all the pixels of the sensor.
“Addition”, “decimation”, and “excision” may be simultaneously performed.
Image sensors can convert data by decimating or adding data at the time of outputting image data.
FIG. 1 is a diagram illustrating a configuration example of a general CMOS image sensor (solid-state imaging device).
A CMOS image sensor 10 of FIG. 1 includes a pixel array section 11, a row scanning circuit 12, a column processing section (readout circuit) 13, a column scanning circuit 14, a timing control circuit 15, and an output interface (IF) circuit 16.
The pixel array section 11 is arranged in a two-dimensional shape (matrix) in which a plurality of pixel circuits 11A-00 to 11A-st have s rows×t columns.
In the CMOS image sensor 10 of FIG. 1, the row scanning circuit 12 drives pixels through a column scanning control line in shutter rows and readout rows depending on controls of a shutter control section and a readout control section of the timing control circuit 15.
The column processing section (readout circuit) 13 reads a signal vsl output to an output signal line lsgn, outputs the read signal to a transfer line ltrf in accordance with column scanning of the column scanning circuit 14, and outputs the signal to the outside using the output IF circuit 16.
In the example of FIG. 1, the column processing section (readout circuit) 13 is constituted by column ADC sections in which an AD converter (ADC: Analog-to-Digital Converter) 13-1 is disposed for each column.
The column ADC section performs A/D conversion in a column unit, outputs the read signal to the transfer line ltrf in accordance with scanning of data after A/D conversion by the column scanning circuit 14, and outputs the signal to the outside using the output IF circuit 16.
FIG. 2 is a block diagram illustrating a configuration example of a data conversion control section including an output system of image data subsequent to the column processing section of the CMOS image sensor of FIG. 1.
A data conversion control section 20 of FIG. 2 includes the output IF circuit 16, a line buffer 17, a reference clock rate converter 18, and a data output section 19.
In this manner, the CMOS image sensor 10 of FIG. 2 performs a rate conversion on data after an A/D conversion process of the column processing section 13 by using the line buffer 17.
Meanwhile, the line buffer 17 is formed by FIFO, SRAM or the like.